The invention relates to a device for sluicing a hot meal-form material, in particular a hot flow of raw cement meal in the cyclone suspension type heat exchanger system of a plant for manufacturing cement clinkers out of raw meal, with a sluice case with upper material inlet, lower material outlet and at least one shuttle valve arranged between the two openings.
Plants for manufacturing cement clinkers out of raw cement meal in accordance with the dry process have a raw meal pre-heater, which as a rule consists of a cyclone suspension type heat exchanger system, into which the raw meal is loaded above, where it moves successively through the cyclone steps in the combined parallel flow/reverse flow to the hot exhaust gas of a pre-calcination step, to be separated from the hot exhaust gas in the lowest cyclone and fed into the feed chamber of the rotary kiln as high-grade pre-calcinated raw cement meal, in whose sintering zone it is burned into cement clinkers. The heated raw meal separated from the flow of exhaust gas in the individually stacked cyclone steps of the cyclone suspension type heat exchanger train is fed into the exhaust pipe section, or the pre-calcinated raw meal from the lowest cyclone step is fed into the rotary kiln feed chamber via vertical or diagonal meal gravity feed pipes or raw meal chutes under the influence of gravity. See for example U.S. Pat. No. 6,444,026, the disclosure of which is incorporated herein by reference.
So-called shuttle sluices or damper boxes, also double shuttle sluices, in which one or two weighted shuttle valves are integrated, are installed in the meal gravity feed pipes. The shuttle valves have the task of holding back the hot gas flow and allowing the hot raw meal flow down through the meal gravity feed pipe after a specific solid load by turning the valves up (Publication xe2x80x9cDrehrohrofenanlagenxe2x80x9d Rotary kiln plants greater than No. 8-100d of KHD Humboldt Wedag AG, 5-84, Pages 8/9). These shuttle valves are subject to great mechanical, chemical and thermal stress and with it, great high thermo-chemical and abrasive wear and tear. Up to now the shuttle valves have been constructed in one piece, i.e., in case of wear and tear the entire shuttle valve had to be removed and repaired or replaced with a new shuttle valve.
The invention is based on the task of creating a device like a shuttle sluice for sluicing or distributing a hot meal-shaped material flow, in particular for cement plants, whose shuttle valve or shuttle valves is or are easy and inexpensive to repair or renew in case of wear and tear.
Characteristic for the shuttle sluice of the invention is the fact that the shuttle valve in the sluice case is constructed not in one piece, but has at least two parts and in two-part design comprises an upper suspension part and a lower expendable part, in particular made of different materials. The upper suspension part, which can be made of a tough, heat-resistant material, and the lower expendable part of the shuttle valve, which consists preferably of a material resistant to heat and wear, are stiff or rigid, i.e., detachably connected to each other, not hinged or pivoted to each other. The size of the expendable part corresponds to that of the lower shuttle valve area, which comes into contact with the hot abrasive meal flow during the damming up and releasing of the periodically backed up flow of hot meal. The upper suspension part and the lower expendable part made of different materials can expand differently and therefore no thermal stresses occur. In case of wear and tear, the upper suspension part and the lower expendable part are simply disconnected and the expendable part is either repaired or replaced with a new part. From case to case, the materials of the two valve parts can be either the same or similar in design.
In the shuttle valve of the invention, the detachable connection between the upper suspension part and the lower expendable part can be designed like a stiff or stiffened joint. In accordance with a special feature of the invention, the upper suspension part and the lower expendable part of the shuttle valve can intermesh at their adjoining sides like a tongue and groove joint, whereby in the tooth area of the intermeshing valve parts two bolts, spaced at a distance from each other, parallel to the swiveling axis of the shuttle valve, are detachably guided through correspondingly aligned passages.
The upper suspension part of the shuttle valve can be composed of a casting, on whose upper side a journal of a shaft is integrally cast on both sides. The two journals of the upper suspension part then form the swiveling axis or full-floating axle of the weighted shuttle valve. The suspension part can also be designed as a weldment. The lower expendable part can be designed as a cast part, welded part or ceramic part.
In accordance with a further feature of the invention, at least the side of the shuttle valve that is subject to wear that is turned away from the material flow to be sluiced can be coated with a fireproof and wear-resistant material. For this purpose, the two parts of the shuttle valve, or at least the lower expendable part, can be designed as composite bodies, comprising of a flat metallic foundation, on which webs of a metallic trellised grate are arranged, whose openings are filled in with a heat-resistant ceramic substance. However, one or both valve parts can also be provided with a different wear-resistant protective coating on one or both surfaces.
The invention and its further features and advantages are illustrated by means of the practical examples schematically displayed in the figures.